Extend the life and versatility of your YSI ProQuatro Multiparameter Water Quality Meter by selecting the exact replacement sensors you need for your field water quality testing program. Designed to work with the ProQuatro handheld and Quatro cable assemblies, these user-replaceable probes and sensors make it easy to swap worn electrodes or reconfigure your meter for new parameters without replacing the entire instrument.

Whether you’re monitoring groundwater wells, surface water, irrigation sources, or industrial discharge, selecting the correct sensor helps ensure accurate, reliable environmental data. 

Looking for the complete instrument?
Visit the ProQuatro Meter & Cable page to purchase the handheld unit and cable assemblies.

Need a Flow Cell or other accessories?
Explore the ProQuatro Accessories page 

ProQuatro Sensors Applications: 

• Groundwater & Well Sampling - Swap DO or ion-selective sensors while sampling wells and aquifers to track contamination and natural baseline conditions.
• Surface Water Field Sampling – Use pH, conductivity, and ORP sensors to support river, lake, and stream assessments for environmental impact studies.
• Drinking Water & Compliance Screening – Replace worn electrodes to maintain EPA-approved water quality reporting accuracy when paired with the main ProQuatro meter.
• Agricultural Water Management – Choose ammonium or nitrate sensors to measure nutrient levels and support irrigation decisions.
• Industrial & Wastewater Management – Replace ORP, pH, or conductivity probes for ongoing monitoring of effluent and process water.
• Aquaculture & Environmental Research – Maintain instrument readiness by easily replacing DO or salinity sensors between sampling campaigns.